In some plasma processing systems, multiple radio frequency (RF) signals are provided to one or more electrodes within a plasma chamber. The RF signals help generate plasma within the plasma chamber. The plasma is used for a variety of operations, e.g., clean substrate placed on a lower electrode, etch the substrate, etc.
Between an RF supply that generates an RF signal and the plasma chamber, an impedance matching circuit is usually placed. The impedance matching circuit matches an impedance of a load, e.g., plasma within the plasma chamber, with an impedance of a source, e.g., an RF power supply. However, in certain situations, the impedance matching is not quick enough to respond to a change in the plasma impedance.
It is in this context that embodiments described in the present disclosure arise.